Alternative to deepcopy for bpy_struct?
Deepcopy is not supported as the Blender objects are optimized for performance.
Most objects have the option, to create a copy by using .copy method

obj = bpy.context.object
copied_obj = obj.copy()


Please note that .copy will also create a new object in the scene (same as duplicate).
Making a fully detached copy of an object, you need to do yourself. as you will by then make a local copy of everything in the python interpreter.

In these cases it is best to do it manual and only select the data you need so the performance can be controlled better.